Chromatographic Methods: A Comprehensive Guide for Chemistry Students

Question 1

In liquid chromatography, the separation of compounds is primarily based on their:

Accepted Answer

Polarity

Answer

Molecular weight

Answer

Boiling point

Answer

Solubility

Question 2

In isocratic chromatography, the composition of the mobile phase:

Accepted Answer

Is constant throughout the separation

Answer

Is changed gradually over the course of the separation

Answer

Is optimized for a specific compound

Answer

Is selected based on the polarity of the analyte

Question 3

Which of the following is a characteristic of a well-resolved chromatographic peak?

Accepted Answer

Narrow and symmetrical

Answer

Broad and asymmetrical

Answer

High and sharp

Answer

Low and wide

Question 4

Which of the following techniques is NOT a type of chromatography method?

Accepted Answer

Electrophoresis

Answer

Gas chromatography

Answer

Liquid chromatography

Answer

High-performance liquid chromatography

Question 5

What primary advantage does high-performance liquid chromatography (HPLC) offer compared to conventional liquid chromatography?

Accepted Answer

Enhanced resolution of peaks

Answer

Faster separation of components

Answer

Lower instrument cost

Answer

Simplified sample preparation procedures

Question 6

How does qualitative analysis differ from quantitative analysis in chromatography?

Accepted Answer

Qualitative analysis identifies compounds, while quantitative analysis determines their amounts.

Answer

Quantitative analysis identifies compounds, while qualitative analysis determines their amounts.

Answer

There is no distinction between qualitative and quantitative analysis in chromatography.

Answer

Both qualitative and quantitative analyses identify and quantify compounds simultaneously.

Question 7

In chromatography, what happens to the retention time of analytes when the temperature is increased?

Accepted Answer

Decreases

Answer

Increases

Answer

Stays the same

Question 8

In addition to UV-Vis detection, which two detection techniques are commonly used in HPLC?

Accepted Answer

Fluorescence

Accepted Answer

Evaporative light scattering detection

Answer

Gas chromatography

Answer

Atomic absorption spectroscopy

Question 9

In chromatography, the retention factor (k) is a measure of:

Accepted Answer

The ratio of analyte concentration in the stationary phase to that in the mobile phase

Answer

The time taken for an analyte to elute from the column

Answer

The selectivity of the separation

Question 10

In chromatography, what is the main function of the mobile phase?

Accepted Answer

Transporting the sample through the system

Answer

Separating components based on size alone

Answer

Reacting with the sample to create new compounds

Answer

Establishing a fixed reference for retention time measurement

Question 11

Which of the following is NOT a type of chromatographic method used to separate compounds?

Accepted Answer

Spectrophotometry

Answer

Gas chromatography

Answer

Liquid chromatography

Answer

High-performance liquid chromatography

Question 12

What is the fundamental principle of gas chromatography?

Accepted Answer

Separation of compounds based on their boiling points and volatility

Answer

Separation of compounds based on their polarity

Answer

Separation of compounds based on their molecular weight

Answer

Separation of compounds based on their charge

Question 13

What is the primary function of a detector in chromatography?

Accepted Answer

To generate a signal proportional to the concentration of separated compounds

Answer

To measure the concentration of separated compounds

Answer

To display the chromatogram

Answer

To control the flow rate of the mobile phase

Question 14

In liquid chromatography, the sample is typically separated on a column packed with:

Accepted Answer

Silica gel

Answer

Glass beads

Answer

Activated carbon

Answer

Sand

Question 15

The primary role of the mobile phase in chromatography is to:

Accepted Answer

Carry the sample through the column

Answer

Detect the sample components

Answer

Quantify the sample components

Answer

Separate the sample components

Question 16

The F-factor in HPLC is primarily used to measure:

Accepted Answer

Column efficiency

Answer

Sample size

Answer

Mobile phase flow rate

Answer

Detector sensitivity

Question 17

Which of the following is an example of a chiral stationary phase used in chromatography?

Accepted Answer

Cyclodextrin

Answer

Alumina

Answer

Silica

Answer

Carbon

Question 18

Gradient elution in chromatography involves:

Accepted Answer

Gradually changing the composition of the mobile phase over time

Answer

Using a constant mobile phase composition

Answer

Reversing the flow direction of the mobile phase

Answer

Increasing the flow rate of the mobile phase

Question 19

Which of the following is NOT a type of chromatographic method?

Accepted Answer

Titration

Answer

High-performance liquid chromatography (HPLC)

Answer

Liquid chromatography (LC)

Answer

Gas chromatography (GC)

Question 20

Which of the following is the stationary phase in gas chromatography?

Accepted Answer

Solid or liquid supported on an inert solid

Answer

Solid

Answer

Liquid

Answer

Gas

Question 21

What is the primary role of the mobile phase in chromatography?

Accepted Answer

To carry the sample through the stationary phase

Answer

To enhance the sensitivity of the detector

Answer

To react with the sample components

Answer

To separate the sample components

Question 22

Which of the following factors affects the retention time of a compound in chromatography?

Accepted Answer

Molecular weight, polarity, and interaction with the stationary phase

Answer

Temperature and pressure

Answer

Flow rate of the mobile phase

Question 23

What is the principle of separation in high-performance liquid chromatography (HPLC)?

Accepted Answer

Differential partitioning of sample components between the mobile and stationary phases

Answer

Differential adsorption of sample components onto the stationary phase

Answer

Differential volatility of sample components

Question 24

What is the primary function of a sample injector in chromatography?

Accepted Answer

To introduce the sample into the chromatographic system

Answer

To detect the separated sample components

Answer

To separate the sample components

Question 25

Which of the following is NOT a quantitative application of chromatography?

Accepted Answer

Identification of unknown compounds

Answer

Analysis of complex mixtures

Answer

Monitoring of chemical reactions

Answer

Determination of the concentration of a compound in a sample

Question 26

What is the main purpose of using a guard column in chromatography?

Accepted Answer

To protect the analytical column from contaminants

Answer

To increase the separation efficiency

Answer

To reduce the analysis time